The field of the invention is the planning and optimization of cellular networks and more precisely the generation of a traffic map.
Within the field of the invention, the notion of traffic is dominant. In fact, whether for evaluating the state of a cellular network through simulations (i.e. planning it) or for configuring it so that it functions optimally with respect to a number of predefined criteria (i.e. optimizing it), it is essential to know how much traffic is to be provided.
It is at least as important to know the distribution of this quantity of traffic in a geographical area covered by the network as to know the quantity of traffic to be provided in this area. In fact, the planning and optimization of a network change according to the position of high-traffic zones called “hotspots”.
As a result, the tools for planning and optimizing cellular networks use “traffic maps”. These traffic maps are constituted by pixels. A pixel represents a discretization of a sub-area of the area of the network. The traffic map associates a value, an expected traffic density, with each of these pixels. This value in general corresponds to the times in the day and in the week during which the quantity of traffic is greatest. Thus, the network is planned in every pixel for the most extreme traffic conditions. The more accurate these maps are, for example the smaller the sub-areas are, the more accurate and faithful to the reality of observations made on the ground the planning and, a fortiori, the optimization of the network in this area are.
However, telecommunication operators do not have direct access to this type of map because they only know the quantity of traffic managed by antennas operated by them, without knowing the exact origin of this traffic in the coverage zones of these antennas.
Radio planning tools are known which make it possible to generate traffic maps for an area of a cellular network from the knowledge of the quantity of traffic collected by each antenna covering at least part of this area. These tools utilize methods that use geographical maps covering the area for which a traffic map will be generated. These methods generally comprise a step of discretizing the area by tiling elements of this area, called pixels, followed by two steps:                a step of associating each pixel with an antenna of the cellular network;        using a geographical map that divides this area according to parcel types, for example rural, road, water, urban, densely urban, and allocating to each parcel type a weighting as a function of the probability that the parcel type is associated with a high traffic density.        
Thus, each pixel of this map is associated with a parcel weighting of the quantity of traffic managed by one of the antennas of the cellular network.
Interestingly, the coverage zone of each antenna is automatically calculated by these planning methods, which estimate the received power at each geographical point coming from each antenna of the network.
In general, the parcel weighting is determined by the telecommunications operator.
The methods utilized by these tools then distribute the traffic captured by each antenna over the coverage zone of this antenna according to the parcel weighting.
One limitation of these methods of generating a traffic map is the accuracy of the map generated. In fact, it cannot be more accurate than the accuracy provided by the geographical map.
The aim of the invention is to propose a generation of a traffic map that is more accurate than the traffic maps currently generated by the known tools.